SFR vs. Capacity, and future-proof valve: a dilemma

Discussion in 'Water Softener Forum, problems, installation and r' started by efreilly, Apr 17, 2011.

  1. efreilly

    efreilly New Member

    Messages:
    4
    Location:
    new jersey
    Hello all. I apologize in advance for posting yet another water softener sizing thread, but I have a dilemma I can't quite wrap my mind around. It mainly stems from the fact that both the SFR and the softening capacity are both proportional to the volume of resin. Here is the problem:

    White scale is ruining our glassware, and it is all over the stainless steel dishwasher and plumbing fixtures. Moreover, we have a Rinnai tankless water heater (9.8gpm) that we are very happy with, but I suspect is very susceptible to this stuff.

    Despite our symptoms, by labwork, our water doesn't seem that terrible;
    Municipal supply; Hardness ~ 10 grains per gallon; ph = 7.3; TDS 153 ppm, iron 0.

    We have two adults and three kids (ages 6,4, and 2), so by conventional calculations, we should use a minimum of 300 gallons per day. Checking my water bills in the last 18 months, I only use about 130 gallons per day -- perhaps because my kids are so young and we have high efficiency appliances. So, even at the higher usage estimate, using a 7-9 day regeneration cycle, I need only about 24,000 grains of capacity.

    On the other hand, we have a 4 full-bathrooms and 2 half-bathrooms. The master shower has an overhead showerhead and two body jet showerheads. We are considering adding a third powder room and a jacuzzi tub in the distant future. (About 31-34 wsfu.) According to the International Plumbing Code, with the number of fixtures in my house, I should have flow downstream from the softener of 25 gallons per minute. (Which probably isn't realistic anyway since I only have about 50psi on a 3/4 inch supply. I think it's one inch into the house, but then the main line into the mechanical closet is smaller.)

    It would take maybe 4 cuft of resin to acheive that flow rate. But I would have to set my salt dose so low, it would be a huge waste of water. With 1.5 cuft of resin, it seems like I would have more than enough capacity, but not nearly enough flow. If I go with a compromise of 2.5cuft of resin, I am concerned that I would have both insufficient flow, and also way too much capacity and wasted water.

    All this, and I would prefer a system flexible enough to handle the changing the water usage of my family as the kids grow up.

    As a compromise, I am zeroing in on a 48000 grain system with 1.5 cuft resin -- ResinTech CG-8 looks like it may allow flow as high as 10gpm/cuft; the rest are all considerably less. Salt dose of 4-6. Regen time override at 9-10 days, and a turbulator to try to minimize channelling. I'm thinking I might have to change to a bigger resin tank if I have issues with bleed-through as the kids get older.

    Finally, I am thinking of a Fleck 5000 SXT since it can theoretically handle up to 21gpm which I may need someday, but I don't read a lot about prople using it. Is there any reason why? Should I just go with a Fleck 5600 SXT instead? I'm a little scared by the flow limitation compared to the 5000.

    Sorry for the long thread, but hopefully the details will help. If anyone can offer a better choice of resin, valve, or overall system design, it would be greatly appreciated.
  2. Akpsdvan

    Akpsdvan In the Trades

    Messages:
    1,495
    Location:
    Alaska
    Likely chance of each and every bathroom going full blast at the same time?
  3. Gary Slusser

    Gary Slusser That's all folks!

    The 5000 is not a popular valve.

    The volume of water used for a regeneration is programmed time wise and flow controlled gpm wise. Yes more resin uses more water to backwash and rinse but it shouldn't be enough to want to live with an undersized softener for many years. And you should do it right the first time.

    You don't need a Turbulator which means you must have a larger DLFC (more gpm during regeneration) and that you can't have a gravel underbed....

    You should use the highest hardness in your city water system, which you can find on the water company's web site in their water quality report, or cal them. The TDS doesn't match the 10 gpg hardness, it should be higher IMO.

    The volume of resin and then the lbs of salt used dictates the K of capacity.

    You need to size with the SFR used in the shower plus any other water use while that shower is using the body sprays. And/or the new tub if you're going to install it say within 4-5 years.
  4. efreilly

    efreilly New Member

    Messages:
    4
    Location:
    new jersey
    Each and every fixture, not much. But we're all at home at the same time, we get ready for school and work at about the same time, and the chance of overlap is high. That's why I'm thinking I should shoot for the 16gpm ballpark rather than the 24gpm ballpark.

    We already have instances of water flow decreasing while the tub is being filled (for the youngest child), and the shower is running (for myself or the older kids), and some other appliance is running (e.g. dishwasher). I expect this will get worse as the kids get older. I realize that a little moderation would solve this problem, but it would be nice to be able to size a softener so I don't have to think about it.

    As implied by the monthly water bill, we're not water hogs, but it seems we tend to use it in spurts all at the same time.
  5. efreilly

    efreilly New Member

    Messages:
    4
    Location:
    new jersey
    Why is the 5000 not a popular valve? Is there a known problem(s) with it?

    The Fleck 7000 specs seems a little overkill for what I need, though the price is similar to the 5000. I am worried that the 5600 could be underpowered for what I might do in the future. Is there any problem with getting an overcapable Fleck 7000SXT valve?

    I am thinking that to get a system with high enough flow, based on my water usage, I'll only need to regenerate every 10-14 days. I've been told channelling is a problem when you go that long. Will the turbulator not help to mitigate that? Is it worth it to have a gravel bed and forgo the turbulator?

    Lastly, if anyone has anything good or bad to say about the ResinTech CG-8 resin, let me know. I'd like to use it as it seems to offer the best flow per cubic foot and I want to keep the volume down since, even at 10-14 day regeneration, it will probably be regenerating more frequently than I need.
  6. Akpsdvan

    Akpsdvan In the Trades

    Messages:
    1,495
    Location:
    Alaska
    With the flow rate that you most likely will have with in the next few years with the up grade of the incoming line either a Fleck 2750 or the 7000 would be better choices.
    If there is a dealer in your area that has the Clack valve that too would be a choice.

    There are two flow rates with any system, the so called normal flow and the peak flow rate.
    With say 2.0 cubic foot of resin and the 2750 valve from Fleck the lower end flow rate would be around 11gpm and a peak of close to the 24 that you might have for short time frames in the future.
    The Fleck 7000 is a bit better with a higher peak flow rate if it has the high flow piston set up.
  7. Gary Slusser

    Gary Slusser That's all folks!

    Originally it had problems and many dealers have stayed away from it since.

    The 7000 is a 1.25" valve, the 5000 is 1" and the 5600 is 3/4". It's kinda like a 2 dr, 4 dr or mini van difference. You don't need a 7000.

    From Fleck... The 5600 should not be used on larger than a 12" dia tank for a softener and a 10" for a filter. A 12" tank is 2.0 cuft and will have a constant SFR of 13 gpm; that is based on the volume of resin which AK always seems always miss.

    A gravel underbed is the best choice because it prevents flow reduction (and channeling), costs less than a Turbulator and uses less water per regeneration because with a Turbulator you must increase the DLFC gpm to get them to work (as I have already told you). Without gravel all those teeny tiny resin beads are pushed up against the slits (measured in thousandths of an inch) in the bottom basket as they try to get through them adn out into your plumbing every time you turn on a fixture in the house (= pressure loss).

    You should reduce water usage in other areas than your water softener. You should regenerate every 7-9 days, that's if you want the softener to operate service free for as long as possible.

    As the kids get older, they will use more water (longer showers and more laundry) but not increase the peak demand flow rate of showers, toilets, tubs etc..

    And you should buy the lowest cost resin you can find, they all do the same job the same way and there's not enough difference in capacity or increased salt efficiency to justify higher prices.

    Your softener regenerates based on gallons used, not time unless you program calendar override (which you should for 7-9 days), unless you use less water than 'normal', which you should program the softener metering based on 60 gals/person/day.
  8. efreilly

    efreilly New Member

    Messages:
    4
    Location:
    new jersey
    clarifications, and a proposed water softener system

    Apparently, I do use much less water than normal -- less than 30 gal/person/day per my water bill. That's the point. Yes, it regenerates based on gallons used, but gallons used is time-sensitive -- the more time goes by, the more gallons I've used.

    Based on the amount of water I use per month, I will almost certainly need to set the override at about 10-14 days. 1.5 cuft of resin at a salt dose of 6lbs/cuft is somewhere around 22000 grains. 150 gallons a day at 10 grains is about 15 days before I get to 22000. I could futz with the salt dose a bit to optimize efficiency, but I'm still looking at an override of 10-14 days by my estimation.


  9. Akpsdvan

    Akpsdvan In the Trades

    Messages:
    1,495
    Location:
    Alaska
    The use of a 10x54 for now with the idea that if more is needed in the future changing to say a 12x54 does sound like an idea... buy the tank and some more resin and you would be good to go as the distributor, gravel and 1.5 cubic foot of resin should trade over to the new tank.
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